Garding's Inequality for Elliptic Operators with Degeneration and its Applications. Variational Dirichlet problem for elliptic operators.
Main publications:
S. A. Iskhokov, M. G. Gadoev, I. A. Yakushev, “Neravenstvo Gordinga dlya ellipticheskikh operatorov vysshego poryadka s nestepennym vyrozhdeniem”, Doklady RAN, 443:3 (2012), 286–289
I.A.Yakushev, “Variatsionnaya zadacha Dirikhle s odnorodnymi granichnymi usloviyami dlya odnogo klassa vyrozhdayuschikhsya ellipticheskikh operatorov v poluprostranstve”, Vestnik Severo-Vostochnogo federalnogo universiteta im. M.K. Ammosova, 10:1 (2013), 9-13
I.A.Yakushev, “O variatsionnoi zadache Dirikhle dlya ellipticheskikh operatorov, vyrozhdayuschikhsya na neogranichennom mnogoobrazii”, Doklady akademii nauk Respubliki Tadzhikistan, 55:7 (2012), 526-532
M. G. Gadoev, I. A. Yakushev, “Variatsionnaya zadacha Dirikhle dlya odnogo klassa ellipticheskikh uravnenii s vyrozhdeniem”, Matematicheskie zametki SVFU, 18:1 (2011), 25-35